@MikeS suggested that a video on extending a jam track might be a good thing. Just as a note, this process is pretty much the same regardless of which DAW software you may have. Only the commands have been changed to protect the innocent. This is how I do it. It is not the only method which can be used, but I have found it to be the quickest way for me to stretch out a jam track.
https://youtu.be/KJ9_w65HZrs
If you would like to hear the complete resulting jam track, you can find it here:
https://fuzzypinkstrap.com/VJR/2020/clean/Let Your Hair Down Ab-Mixdown.mp3
If you would like to hear the complete resulting jam track, you can find it here:
https://fuzzypinkstrap.com/VJR/2020/clean/Let Your Hair Down Ab-Mixdown.mp3